Website | Join our Slack! | Browse API | Quick Start / Documentation | Follow on Twitter

Ultralight is a lightweight, cross-platform, pure-GPU, HTML rendering engine for desktop apps and games. It supports most modern HTML5 and JavaScript features while still remaining small in binary size and memory usage.

API is currently available for C and C++, with bindings for more languages in development.

Ultralight is a new port of WebKit combined with a new 2D GPU renderer intended specifically for embedding in apps and games.

The renderer emits virtual GPU commands that are translated into native GPU commands of the target platform at runtime. This approach makes it easy to embed Ultralight in games as well.

Ultralight grants developers the ability to override low-level system calls for deeper integration with applications. We currently provide APIs to customize File System and Font Loading but will soon be expanding this to Clipboard, Memory Allocation, Network Requests, and more.

AppCore is an optional, cross-platform desktop app runtime built on top of Ultralight that handles window creation, native event loops, native graphics drivers (D3D11, D3D12, Metal, OpenGL), and more.

You can use it to build desktop HTML apps in a manner similar to Electron. It's currently under active development and only supports single-window apps at this writing. A number of planned features (app icons, automatic packager, borderless windows with custom draggable titlebars, etc) are missing but on the way.

Ultralight is designed to integrate well into existing game engines. In this case you would just use the low-level Ultralight API (not AppCore) and implement the GPUDriver interface for your target platform (we recommend using the drivers and shader code in the AppCore repo as a base).

Ultralight is free for non-commercial use and free for commercial use by companies with less than $100K gross annual revenue. For more info see LICENSE.txt

We offer commercial licensing, priority support, and source code. To learn more, please visit our website.

You can get the latest SDK for each platform via the following links:

• Windows | x64 | Release
• Windows | x86 | Release
• Linux | x64 | Release
• macOS | x64 | Release

Debug packages are also available below:

• Windows | x64 | Debug
• Windows | x86 | Debug
• Linux | x64 | Debug
• macOS | x64 | Debug

Note: Full debug symbols are only provided for WebCore and AppCore modules.

Pre-built binares are uploaded to the following S3 buckets every commit:

• Release Bins: https://ultralight-sdk.sfo2.cdn.digitaloceanspaces.com/
• Debug Bins: https://ultralight-sdk-dbg.sfo2.cdn.digitaloceanspaces.com/

Click any of the links for an XML listing of available files.